Since we know Demolisher is taken out could scavenger be his twin? Skidz and mudflap split apart in there protoform as they burned through the atmosphere could these two giants have done the same and soundwave just gave them the same alt mode? just throwing a crazy thought out there.

Not unusal in any TF universe especailly G1. considering that they had vehical modes on cybertron it would be to outlandish to say there are more than one type of vehical especally in terms of cybertroniain contruction vehicals just like on earth we dont have only one digger, one craine etc mass production is our friend however it is its spark that gives there personality and makes them individual they maybe the same type of digger on cybertron and earth but entirley different personallities think of it like the seekers in G1 they where all cybertonian jets but completely different in personality.